The present invention relates to repair patches for the protective sheets of containers and lorries.
In the event of damage, sheets which are used to cover the loading openings of containers, lorries or the like used in international goods transportation, must be repaired in such a way that the customs seal is preserved. To make such a repair, the procedure hitherto has been to detach at least part of the sheet from the container or vehicle, lay it on a solid, flat support and then apply the repair patch to the damaged area. To meet customs regulations, after it has been applied the patch which is to be welded to the sheet must be sealed with an additional plastics strip, and the sealing strip must be welded on where it overlaps with the edge of the patch in the same welding operation as is used to weld the patch to the sheet. For this purpose, the patch is first of all laid on the detached sheet and then the beginning of the sealing strip is placed in position separately with its centre on the edge of the patch, after which a hand welding device is used to perform the welding operation, which takes place around the entire circumference of the patch, the sealing strip being guided separately with the other hand.
Because of the time-consuming detachment and re-attachment of the sheet to be repaired and because of the often adverse weather conditions on the site, generally in a port, and furthermore because of the considerable size and thus weight of the sheet, the repair operations are time-consuming and laborious. However, apart from this, even an expert can only carry out the operation if he works very carefully since it is extremely difficult to weld the relatively narrow sealing strip, which has to be guided separately by hand, around the entire circumference of the path covering its edge and accurately and leaving a sufficient margin for the seal made with the strip to be acknowledged as secure from the customs point of view. Since such repairs are very difficult to make on site, the sheets have to be taken to a repair shop, meaning that, as will be appreciated, the repair becomes very expensive or even that, in certain circumstances, it cannot be made for lack of skilled personnel.
It is an object of the invention to provide a repair patch for sheets which are intended in particular for covering the loading openings of containers used in international goods transportation, which is prepared ready for use, in such a way that it is easy even for unskilled labor to weld it on site, to the sheet to be repaired, in such a way that the repair can be considered secure from the customs point of view.